cooksey



June 20, 1961 w. H. COOKSEY 2,989,601

INTERRUPTERS FOR ENGINE SPARK-IGNITION APPARATUS Filed June 12, 1959 2Sheets-Sheet 1 June 20, 1961 w. H. COOKSEY INTERRUPTERS FOR ENGINESPARK-IGNITION APPARATUS Filed June 12, 1959 2 Sheets-Sheet 2 LzvezztorNH Cooks 6y United States Patent FOR ENGINE SPARK-IGNITION AEPPAERATUSWilliam Harold Cooksey, Walsall, England, assignor to Joseph Lucas(Industries) Limited, Birmingham, England Filed June 12, 1959, Ser. No.819,959 Claims priority, application Great Britain June 19, 1958 3Claims. (Cl. 200-30) T This invention relates to an electric currentinterrupter mechanism for an engine spark-ignition apparatus of the kindin which the interrupter is mounted on a carrier having freedom ofangular movement relatively to a fixed supporting member, theinterrupter comprising a pair of contact pieces which are separable bythe. action of a rotary cam on a spring-loaded arm to which one of thecontact pieces is attached. The angular movement of the interrupterserves to vary the ignition timing and may be effected manually or by agovernor responsive to, for example, the pressure in the air-intakemanifold of the engine,

. When an:interrupter mechanism of the said kind is in action the camintermittently exerts on the arm associated with the movable contactpiece a radially directed force which tends to produce an undesirabledeflection of the plane of the interrupter carrier in consequence of thesmall amount of slackness which inevitably exists in the bearing bywhich the carrier is mounted on the supporting member. One eifect ofthis deflection is to impair the desired smoothness of the angularmovement of the carrier. Another is to cause unequal separation of thecontact pieces with resulting irregularity of the ignition timmg.

The object of the present invention is to provide an improvedconstruction whereby the aforesaid disadvantages can be obviated.

An interrupter mechanism of the kind above specified and in accordancewith the invention includes a triangular arrangement of three abutmentswhich provide a three point support between the interrupter carrier andthe supporting member, two of which abutment pieces serve as fulcrumpoints and the third of which serves as a stop, and a spring loadedprojection extending from the interrupter carrier through an aperture inthe supporting member, the arrangement being such that the stop preventstilting of the interrupter carrier relatively to the supporting memberby the impacts of the cam.

In the accompanying drawings:

FIGURE 1 is a front elevation of an interrupter mechanism embodying theinvention.

FIGURE 2 is a sectional side view on the line 22 of FIGURE 1.

FIGURE 3 is a sectional plan on the line 33 of FIGURE 1.

FIGURE 4 is a plan and FIGURE 5 a rear elevation of the mechanism.

FIGURE 6 is a perspective view illustrating a detail feature to behereinafter described.

Referring to the drawings, the supporting member 10 consists of a metalplate of circular or other shape adapted to be secured within thehousing of the mechanism by screws inserted through lugs 11. At thecentre of this plate is formed an annular boss 12 which serves as thebearing for the interrupter carrier 13; the latter consisting of a metalplate of any convenient shape and having therein a circular aperture toreceive the boss on the supporting member. On the said carrier plate issecured the fixed contact piece 14 of the current interrupter, and apost 15 which serves as the pivot for an arm 16 made from electricalinsulating material. To this arm is attached a spring blade 17 on thefree end of which is se- ICC erateswith the rotary arm-actuating cam 20whereby the contact pieces are intermittently separated.

On the interrupter carrier 13 is also formed an arm 21. for connectionto any desired means for imparting angular movement to the carrierrelatively to the supporting member for varying the ignition timing asabovementioned.

In applying the invention to such mechanism there are secured to orformed on the rear of the interrupter carrier plate 13 three abutments22, 23, 24 which bear against the adjacent face of the supporting member10, the abutments being arranged in a triangular disposition as shown inFIGURE 1. The abutments 22, 23 serve as fulcrum points about which aslight tilt can be imparted to the plate 13'to bring the abutment 24(which serves as a stop) into contact with the supporting member 10. Theposition of the abutment 24 is such that it is located on a radial linedrawn through it and the tip 19 of the arm 16.

At a position adjacent to the stop 24 there is secured to the rear ofthe carrier plate 13 a projection 25 which extends through an arcuateslot 26 in the supporting member 10, and on this projection is formed orsecured a head 27 which is shaped to present two surfaces 28 which areinclined in opposite directions at a small angle to the adjacent rearface of the supporting member. Also there is provided between the headand the supporting member a slipper 29 consisting of a thin metal platewhich lies in contact with the supporting member. The slipper is shownseparately in FIGURE 6. In it is formed a notch 30 through which passesthe projection 25, and a slot 31 which receives one end of a tag 32secured to the projection, and serving to hold the plate in position.Further, there are formed on the opposite side edges of the slipper apair of tongue pieces 33 which abut against the ends of the head 27 sothat when the carrier plate 13 receives an angular movement, thecombined actions of the projection 24 and head 27 on the slipper serveto impart a corresponding sliding movement of the slipper on thecontiguous surface of the supporting member 10.

For holding the stop 24 in permanent contact with the member 10, thereis mounted on the rear side of the said member a light spring consistingof a wire 34. This wire is coiled around a post 35 on the member 10, atthe side of the boss 12 remote from the slot 26, and its free ends liein the tapering gaps between the slipper 29 and the inclined edges 28 ofthe head 27. As the free ends of the spring wire tend to move towardseach other they set up a wedging action on the head 27 which holds thestop 24 in permanent contact with the member 10. Moreover, due to theposition of the post 35 any angular movement of the carrier 13 relativeto the member 10 will result in movement of the free ends of the springwire in the gaps between the slipper 29 and the edges 28, thus avoidingrisk of seizure.

The arrangement is such that the interaction of the stop 24 andsupporting member 10 resists the impact of the cam 20 on the tip 19 ofthe arm 16, each time that the contact pieces 14 and 18 are separated,and so prevents tilting of the interrupter carrier 13 relatively to thesupporting member.

The invention is not, however, limited to the particular example abovedescribed as subordinate details may be varied. Thus the abutments 22,23 and 24 may be formed on or attached to the supporting member, andinstead of the wire spring 34, any other convenient spring means may beprovided, such as a spring blade secured to the head 27 and having afree end which bears on the rear face of the member 10.

Having thus described my invention what I claim as new'and desireto'seeure by Letters Patent is:

1. An electric current interrupter for an engine sparkignitionapparatus, comprising in combination a fixed suporting member, a contactcarrier' liaving' angular freedom of movement relative to saidsupporting'm'e'mber, a springloaded arm pivotally mounted on saidcarrier, a pair of mutually engageablecontact pieces respectivelymounted on said carrier and spring-loaded arm so that the latter tendsto urge the contact piece thereon into contact with the other contactpiece, a rotary cam arranged to act intermittently on said arm" foreifecting' separation of said contact pieces, a' triangular arrangementof three abutmentpieces through the medium of which said carrier'issupported by said supporting member, two of said abutment'pieces formingfulcrum points about which said arm tends to tiltsaid carrier under theaction of said cam, and

the third abutment piece forming a stop for preventing 4 a lineextending from the axis of said carrier through the part ofsaid arm onwhich said cam acts so that tilting of said carrier under the action ofsaid cam is prevented by said third abutment piece.

2. An electric current interrupter according to claim 1, and comprisinga slipper bearing against said supporting member and engaged by theprojection on said carrier so as to be movable therewith relative tosaid supporting member, the head on said projection being shaped toprovide between it and said slipper a pair of tapering gaps, and freeends of said spring being located in said gaps so as to exert awedging'action on saidhead.

3. An electric current interrupter according to claim 2, and comprisinga post which is mounted on said supporting member; and about which saidspring is coiled so that the free" ends" of said spring are caused tomove in said" tapering gaps during angular movement of said carrierrelative" to'said supporting member.

References Cited in the file of this patent I UNITED STATES PATENTS2,471,318 Fit'zsimmons et al May 24, 1949 2,487,231. Fitzsimmons et alNov. 8, 1949 2,610,264 Fitzsiinmons et a1 Sept. 9, 1952 2,801,304Winkley July 30, 1957 2,816,968 Julian et a1 Dec. 17; 1957

